The invention relates to foam compositions, precursors thereof and methods for making foam compositions and foam containing articles.
Foams are employed in a wide range of commercial applications including applications requiring thermal and sound insulation such as automotive and construction environments, among others. In the automotive industry, foams are typically formed in situ, and can be used to fill cavities such as pillars and rocker panels, and to dampen sound transmission. In situ foam formation has typically been accomplished by using a polyurethane foam based on isocyanate chemistry. Certain polyurethane foam components and by-products thereof are believed to have an undesirable environmental impact. Consequently, there is a need in this art for a low-temperature foam which is cost-effective and substantially free of undesirable materials.
The invention is capable of solving problems associated with conventional foam formulations by providing foam compositions and precursors thereto which do not require the use of isocyanates. The inventive compositions and precursors can thereof reduce, if not eliminate, the presence of conventional undesirable compounds and by-products thereof while providing benefits associated with conventional foams, e.g, sound/vibration dampening, thermal insulation, structure reinforcement, floatation, energy dissipation, among other benefits. In addition, the inventive foam has a reduced cured and tack time in comparison to conventional polyurethane foams. These properties in turn improve the efficiency of manufacturing processes that employ foam.
One aspect of the invention relates to a method of reacting an epoxy compound and a hydrogen donor or acid compound at ambient conditions to produce a foam. This reaction can produce a relatively large exotherm. The heat released by the exothermic reaction can be sufficient to drive an endothermic blowing agent, thus creating a foam virtually instantaneously. In fact, the exothermic reaction can be sufficiently large to cause a blowing agent entrapped within, for example, thermoplastic powders to expand thereby forming a foam.
Another aspect of the invention relates to a method of containing the foam during expansion by expanding the foam within a containment or control means. The control means confines the expanding foam and determines the direction of expansion. While any suitable control means can be employed, a polymeric bag or sack is desirable. If desired, the polymer bag comprises an adhesive material, e.g., the bag adhesive is activated by the exothermic foam reaction and affixes the resultant foam to a substrate. The polymeric bag can be fabricated from a virtually unlimited array of materials and configured into any desirable shape, e.g., a honeycomb structure, replicating an automotive cavity, etc.
The inventive foam can be employed in a wide array of end-uses. Examples of such uses include thermal insulation such as appliances, e.g., refrigerators, hot water heaters, etc; aircraft; commercial or residential construction such as spray or rigid insulation for walls, doors, cavity/widow sealant, acoustical control, etc.; packing material, e.g., foam-in-place; marine foams; environmental control, e.g., spill containment; footware; furniture; toy and consumer goods; protective equipment such as pads, helmets, etc.; fluid filtration; transportation industry uses, e.g., sound dampeners, structural supporting material, etc. for cars, trucks and heavy duty vehicles; vehicle repair; gasketing material; medical uses such as casts, emergency immobilization, etc.; artistic medium such as decorative brick/block, figures, etc.; among others.